MRI Image Quality Exam Questions
with Correct Answers (Verified
Answers) Plus Rationales 2026 Q&A |
Instant Download Pdf
Question 1
Which parameter primarily determines the amount of longitudinal recovery
before the next excitation?
A. TE
B. TR
C. Bandwidth
D. Echo train length
Rationale: TR, or repetition time, is the interval between successive excitation
pulses applied to the same imaging location. It strongly influences longitudinal
magnetization recovery and therefore affects image contrast and signal.
Question 2
What is the primary effect of increasing TE in a conventional spin-echo sequence?
A. Increased T1 weighting
B. Reduced T2 weighting
C. Elimination of susceptibility effects
D. Increased T2 weighting
Rationale: A longer TE allows more transverse relaxation to occur before the
signal is measured. This increases the influence of T2 decay and therefore
increases T2 weighting.
Question 3
,Which change generally improves in-plane spatial resolution?
A. Increasing voxel size
B. Increasing slice thickness
C. Increasing the acquisition matrix while maintaining the same FOV
D. Increasing the number of signal averages only
Rationale: Increasing the matrix while keeping FOV constant decreases pixel
dimensions. Smaller pixels provide finer in-plane spatial resolution, although the
resulting reduction in signal per pixel can reduce SNR.
Question 4
A sequence uses a 240-mm frequency-direction FOV and a 256-element
frequency matrix. What is the approximate pixel dimension in that direction?
A. 0.24 mm
B. 0.94 mm
C. 1.07 mm
D. 2.56 mm
Rationale: Pixel size = FOV ÷ matrix size. Thus, 240 mm ÷ 256 ≈ 0.94 mm.
Question 5
Which change generally increases SNR without changing the basic tissue contrast?
A. Increasing the number of signal averages
B. Increasing TE substantially
C. Decreasing TR substantially
D. Increasing susceptibility effects
Rationale: Increasing the number of signal averages (NEX/NSA) improves SNR by
averaging repeated measurements. The tradeoff is increased acquisition time.
Question 6
,What happens to scan time when the number of phase-encoding steps is
increased, assuming other factors remain constant?
A. Scan time decreases
B. Scan time remains unchanged
C. Scan time becomes independent of TR
D. Scan time increases
Rationale: More phase-encoding steps require more data acquisitions. With
other parameters unchanged, this increases acquisition time.
Question 7
Which change generally produces smaller in-plane pixels?
A. Increasing FOV while maintaining matrix
B. Decreasing matrix while maintaining FOV
C. Decreasing FOV while maintaining matrix
D. Increasing slice thickness
Rationale: Pixel dimension is determined by FOV divided by matrix size. Reducing
FOV while maintaining the same matrix therefore produces smaller pixels and
higher in-plane spatial resolution.
Question 8
What is the principal disadvantage of reducing FOV while maintaining the same
matrix?
A. Increased voxel size
B. Reduced spatial resolution
C. Increased slice thickness
D. Reduced signal per pixel and potentially lower SNR
Rationale: A smaller FOV with the same matrix produces smaller pixels. Although
spatial resolution improves, each pixel contains less signal, which can reduce SNR.
, Question 9
Which factor directly affects through-plane spatial resolution?
A. Frequency bandwidth only
B. Number of phase-encoding steps only
C. Slice thickness
D. TE only
Rationale: Slice thickness determines the dimension of the voxel in the through-
plane direction. Thinner slices improve through-plane spatial resolution but
generally reduce SNR.
Question 10
What is partial-volume averaging?
A. Increased noise caused by insufficient averages
B. Averaging of different tissues within the same voxel
C. Duplication of anatomy caused by motion
D. Loss of signal caused by RF leakage
Rationale: Partial-volume averaging occurs when a voxel contains more than
one tissue type. Their signals are combined, potentially obscuring small structures
or reducing apparent contrast.
Question 11
Which change generally reduces partial-volume averaging?
A. Increasing slice thickness
B. Increasing voxel dimensions
C. Increasing FOV without changing matrix
D. Using thinner slices
Rationale: Thinner slices reduce voxel volume in the through-plane direction.
This decreases the amount of different tissue types contained within an individual
voxel.
with Correct Answers (Verified
Answers) Plus Rationales 2026 Q&A |
Instant Download Pdf
Question 1
Which parameter primarily determines the amount of longitudinal recovery
before the next excitation?
A. TE
B. TR
C. Bandwidth
D. Echo train length
Rationale: TR, or repetition time, is the interval between successive excitation
pulses applied to the same imaging location. It strongly influences longitudinal
magnetization recovery and therefore affects image contrast and signal.
Question 2
What is the primary effect of increasing TE in a conventional spin-echo sequence?
A. Increased T1 weighting
B. Reduced T2 weighting
C. Elimination of susceptibility effects
D. Increased T2 weighting
Rationale: A longer TE allows more transverse relaxation to occur before the
signal is measured. This increases the influence of T2 decay and therefore
increases T2 weighting.
Question 3
,Which change generally improves in-plane spatial resolution?
A. Increasing voxel size
B. Increasing slice thickness
C. Increasing the acquisition matrix while maintaining the same FOV
D. Increasing the number of signal averages only
Rationale: Increasing the matrix while keeping FOV constant decreases pixel
dimensions. Smaller pixels provide finer in-plane spatial resolution, although the
resulting reduction in signal per pixel can reduce SNR.
Question 4
A sequence uses a 240-mm frequency-direction FOV and a 256-element
frequency matrix. What is the approximate pixel dimension in that direction?
A. 0.24 mm
B. 0.94 mm
C. 1.07 mm
D. 2.56 mm
Rationale: Pixel size = FOV ÷ matrix size. Thus, 240 mm ÷ 256 ≈ 0.94 mm.
Question 5
Which change generally increases SNR without changing the basic tissue contrast?
A. Increasing the number of signal averages
B. Increasing TE substantially
C. Decreasing TR substantially
D. Increasing susceptibility effects
Rationale: Increasing the number of signal averages (NEX/NSA) improves SNR by
averaging repeated measurements. The tradeoff is increased acquisition time.
Question 6
,What happens to scan time when the number of phase-encoding steps is
increased, assuming other factors remain constant?
A. Scan time decreases
B. Scan time remains unchanged
C. Scan time becomes independent of TR
D. Scan time increases
Rationale: More phase-encoding steps require more data acquisitions. With
other parameters unchanged, this increases acquisition time.
Question 7
Which change generally produces smaller in-plane pixels?
A. Increasing FOV while maintaining matrix
B. Decreasing matrix while maintaining FOV
C. Decreasing FOV while maintaining matrix
D. Increasing slice thickness
Rationale: Pixel dimension is determined by FOV divided by matrix size. Reducing
FOV while maintaining the same matrix therefore produces smaller pixels and
higher in-plane spatial resolution.
Question 8
What is the principal disadvantage of reducing FOV while maintaining the same
matrix?
A. Increased voxel size
B. Reduced spatial resolution
C. Increased slice thickness
D. Reduced signal per pixel and potentially lower SNR
Rationale: A smaller FOV with the same matrix produces smaller pixels. Although
spatial resolution improves, each pixel contains less signal, which can reduce SNR.
, Question 9
Which factor directly affects through-plane spatial resolution?
A. Frequency bandwidth only
B. Number of phase-encoding steps only
C. Slice thickness
D. TE only
Rationale: Slice thickness determines the dimension of the voxel in the through-
plane direction. Thinner slices improve through-plane spatial resolution but
generally reduce SNR.
Question 10
What is partial-volume averaging?
A. Increased noise caused by insufficient averages
B. Averaging of different tissues within the same voxel
C. Duplication of anatomy caused by motion
D. Loss of signal caused by RF leakage
Rationale: Partial-volume averaging occurs when a voxel contains more than
one tissue type. Their signals are combined, potentially obscuring small structures
or reducing apparent contrast.
Question 11
Which change generally reduces partial-volume averaging?
A. Increasing slice thickness
B. Increasing voxel dimensions
C. Increasing FOV without changing matrix
D. Using thinner slices
Rationale: Thinner slices reduce voxel volume in the through-plane direction.
This decreases the amount of different tissue types contained within an individual
voxel.
